Brazing alloy



Patented June 6, 1939 UNITED STATES PATENT OFFICE BRAZING ALLOY Philip R. Kalischer, Wilkinsburg, Pa., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania No Drawing. Application March 31, 1939,

Serial No. 265,228

' 4 Claims. (01. 75-153) tile as applied or as fused in a joint, the ductility preferably approaching that of the well known 50% silver solders. Further, the alloy should have the characteristics of wetting metal parts without i the use of a flux and of adhering to ferrous and non-ferrous metals.

An object of this invention is to provide a copper phosphorus brazing alloy having improved characteristics.

- A more specific object of this invention is to provide a brazing alloy of copper, phosphorus and antimony having a low flow point, ductility as fused and the ability to adhere to non-ferrous metals and alloys. I 1' Other objects of this invention will be apparent from the following description and the appended claims.

The alloy of this invention comprises antimony in an-amount varying approximately from .l%

to 6%, phosphorus varying approximately from 4% to 10% and the balance substantially all copper. In a preferred embodiment of the invention, 'the alloying elements are present in an amount ranging from 4 to 8% of phosphorus and from .5% to 4% of antimony with the balance substantially all copper.

In producing this brazing alloy, it is found that the antimony addition is very effective in lowering the flow point of the alloy without detri- 40 mentally affecting its ductility. In a number of cases it is found that the alloys whose contents fall within the ranges given hereinbefore where antimony is employed in place of the part of the phosphorus of the alloy, have a greater ductility than corresponding alloys which have a phosphorus content equal to the antimony plus phosphorus content of the alloy of this invention.

As illustrative of theafl'ect of antimony additions on the flow point of the resulting copperphosphorus-antimony alloy, reference may be had to the following table from which it is apparent that the antimony inclusions, both as additions to copper and phosphorus and as substitutions for part of the phosphorus content of while having a ductility far such alloys, have a definite eifect in reducing the flow point of the resulting alloy.

Alloy No Pegcbpnt Pcrroent Pecltlant Flovgsoint, 5

The relationship given in the table has been found over a wide range of alloy compositions where the antimony plus phosphorus content in the copper base is from 5% to 10% of the whole.

In practice, it is found that the best combination of characteristics of the alloy is obtained where the phosphorus plus antimony content is from 7% to 8% with the antimony present in amounts from .5 up to 4%, the resulting alloy having a low flow point, high ductility and extremely good selffluxing characteristics. As employed in this description, the term flow point means the lowest temperature at which the alloy is completely fluid and as applied to the alloys of this invention, is also the melting point of the alloys, it being found that they have a very sharp melting point, so the individual alloys having no melting range. The alloy; identified in the table as No. 13 is of unusual value having a flow int below 700 C.

eater, as determined by bending a brazing joint, than the ductility obtained with a copper base alloy containing only 7% of phosphorus. In addition, this alloy adheres well to non-ferrous metals, no flux being necessary.

The copper-phosphorus-antimony alloys of this 40 invention may be prepared by process anal- O ous to those known to the art for the manufacture of other alloys. Thus a melt of copper and phosphorous having the desired-phosphorus content may be made to which the antimony in the correct proportions may be added or the antimony and copper may be. melted together, after which the phosphorus may be added in the correct proportions. The resulting alloy can be cast, and fabricated to a desired shape'or form, 50 or may be prepared for use as a powdered alloy. Whether employed in the solid form or in the powdered form, strong, dense and ductile welds are formed with non-ferrous metals and without any fluxing agent, since the resulting alloy has .2. A M: oy

of phosphorus and from .5% to 4% of antimony with the balance substantially all copper.

3. A brazing alloy composed of about 6% of phosphorus, about 2% of antimony and about 92% of copper,

4. A brazing alloy consisting of 6% to 7.5% of phosphorus, .5% to 2% of antimony, the combined phosphorus and antimony content ranging between 7% and 8%, and the balance substantially all copper. 

